Journal
JOURNAL OF PHYSICAL CHEMISTRY B
Volume 104, Issue 47, Pages 10978-10988Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp000555g
Keywords
-
Categories
Ask authors/readers for more resources
The adsorption of carbon dioxide onto M-ZSM-5 zeolites (M = Li, Na, K, Cs) was studied by means of FTIR spectroscopy and adsorption microcalorimetry. Quantum chemical calculations, at the B3-LYP level, on the interaction of CO2 with the bare alkali-metal cations were performed to assist interpretation of the experimental results. With the likely exception of Li+, CO2 was found to undergo a two-step interaction with the metal ions. At a low equilibrium pressure linear 1:1 adducts of the type M+. . .O=C=O (M = Na+, K+, Cs+) are formed; upon increasing the CO2 equilibrium pressure, the metal cation coordinates a second CO2 molecule, forming a 2:1 adduct. Calculated (ab initio) bond lengths for the 1:1 adduct are given, as well as corresponding values of the binding energy and enthalpic term. Experimentally derived values of the main thermodynamic functions (DeltaH(degrees), DeltaG degrees, and DeltaS degrees) are discussed and correlated with detailed results from IR spectroscopy. The interaction cation/CO2 alone cannot account for the body of evidence, and the contribution of nearby O2- anions has to be invoked.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available